Gonococci that express Opa proteins generally acquire positive charge which derives from these outer membrane proteins presenting clusters of excess basic amino acids (lysine, arginine, histidine) on their surfaces. Production of Opa proteins by gonococci, as is typical in gonorrheal urethritis of males, endows the bacteria with abilities to adhere to and be ingested by epithelial cells whose heparan sulfate-bearing glycoproteins have been shown to act as "receptors" for Opa+ gonococci. Polyanionic polymers such as heparin, dextran sulfate, and DNA accrete on surfaces of Opa+ gonococci with several consequences depending on their size and charge.